Electrophotographic photoreceptor, electrophotographic apparatus comprising the same, and package of electrophotographic photoreceptor

Abstract

In a negatively-chargeable laminate-type electrophotographic photoreceptor, a charge generation layer and another charge transport layer are arranged on a conductive substrate directly or via an intermediate layer. The charge transport layer contains at least a hole-transporting substance, an electron-transporting substance and a binder resin; the mass ratio (R PN ) [% by mass] between mass (P) of the hole-transporting substance and mass (N) of the electron-transporting substance is represented by the following equation (1), and satisfies the following equation (2): R PN =( N /( P+N ))×100  (1) 1≦ R PN ≦40  (2); and when a voltage of +6 kV is applied to the photoreceptor for 5 seconds via a resin sheet having a thickness of 50 μm and a surface resistivity of 2×10 7 Ω/cm 2 , the surface potential difference (ΔVo) and half-tone potential difference (ΔVh) between before and after the voltage application are both 15 V or less.

What is claimed is: 
     
       1. A negatively-chargeable laminate-type electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are arranged in the order mentioned on a conductive substrate directly or via an intermediate layer, wherein:
 said charge transport layer comprises at least a hole-transporting substance, an electron-transporting substance and a binder resin; 
 the mass ratio (R PN ) [% by mass] between the mass (P) of said hole-transporting substance and the mass (N) of said electron-transporting substance, which mass ratio is represented by the following equation (1), satisfies the following equation (2):
     R   PN =( N /( P +N ))×100  (1)
 
   1 ≦R   PN ≦40  (2); and
 
 
 when a voltage of +6 kV is applied to said electrophotographic photoreceptor for 5 seconds via a resin sheet having a thickness of 50 μm and a surface resistivity of 2×10 7  Ω/cm 2 , the surface potential difference (ΔVo) and half-tone potential difference (ΔVh) between before and after application of said voltage are both 15 V or less. 
 
     
     
       2. The electrophotographic photoreceptor according to  claim 1 , wherein at least one of said electron-transporting substance is a compound having a structure represented by the following Formula (ET1): 
       
         
           
           
               
               
           
         
         (wherein, R 1  and R 2 , the same or different, represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group optionally having a substituent, a cycloalkyl group, an aralkyl group optionally having a substituent or a halogenated alkyl group; 
         R 3  represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group optionally having a substituent, a cycloalkyl group, an aralkyl group optionally having a substituent or a halogenated alkyl group; 
         R 4  to R 8 , the same or different, represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group optionally having a substituent, an aralkyl group optionally having a substituent, a phenoxy group optionally having a substituent, a halogenated alkyl group, a cyano group or a nitro group, or two or more of said groups optionally bind with each other to form a ring; and 
         said substituents represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, a cyano group, an amino group, a nitro group or a halogenated alkyl group). 
       
     
     
       3. The electrophotographic photoreceptor according to  claim 1 , wherein at least one of the electron-transporting substance is a compound having a structure represented by the following Formula (ET2): 
       
         
           
           
               
               
           
         
         (wherein, R 9  to R 14 , the same or different, represent a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group optionally having a substituent, a heterocyclic group optionally having a substituent, an ester group, a cycloalkyl group, an aralkyl group optionally having a substituent, an allyl group, an amide group, an amino group, an acyl group, an alkenyl group, an alkynyl group, a carboxyl group, a carbonyl group, a carboxylate group or a halogenated alkyl group; and 
         said substituents represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, a cyano group, an amino group, a nitro group or a halogenated alkyl group). 
       
     
     
       4. The electrophotographic photoreceptor according to  claim 1 , wherein at least one of the electron-transporting substance is a compound having a structure represented by the following Formula (ET3): 
       
         
           
           
               
               
           
         
         (wherein, R 15  and R 16 , the same or different, represent a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group optionally having a substituent, a heterocyclic group optionally having a substituent, an ester group, a cycloalkyl group, an aralkyl group optionally having a substituent, an allyl group, an amide group, an amino group, an acyl group, an alkenyl group, an alkynyl group, a carboxyl group, a carbonyl group, a carboxylate group or a halogenated alkyl group; and 
         said substituents represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, a cyano group, an amino group, a nitro group or a halogenated alkyl group). 
       
     
     
       5. An electrophotographic apparatus comprising:
 the electrophotographic photoreceptor according to  claim 1 ; 
 a charging means which charges said electrophotographic photoreceptor; 
 an exposure means which exposes the thus charged electrophotographic photoreceptor to form an electrostatic latent image; 
 a developing means which develops said electrostatic latent image formed on said electrophotographic photoreceptor with a toner to form a toner image; 
 a transfer means which transfers said toner image formed on said electrophotographic photoreceptor to a recording medium; and 
 a fixation means which fixes said toner image transferred to said recording medium. 
 
     
     
       6. A package of an electrophotographic photoreceptor, in which the electrophotographic photoreceptor according to  claim 1  is covered with a black sheet article,
 wherein said black sheet article has a thickness of 30 to 80 μm and a surface resistivity of 10 2  to 10 11  Ω/cm 2 .